Dip-Pen Nanolithographic® (DPN)® printing has been developed in various embodiments as a scanning probe-based technique that uses, at least in some embodiments, a coated sharp tip such as an atomic force microscope (AFM) tip to pattern surfaces on, for example, the sub-50 nm to many micrometer length scale (see, for example, Piner et al. Science 283, 661-663 (1999)). This novel printing technique in its various embodiments can combine soft matter compatibility with the high resolution of scanning probe and AFM methods, thereby affording unique opportunities to use micro- and nano-patterned substrates in a variety of fields ranging from molecular electronics to biomedicine. However, an obstacle in commercially utilizing DPN printing for some applications has been its relatively low throughput (see, for example, Hong et al. Science 288, 1808-1811 (2000); Salaita et al. Small 1, 940-945 (2005)), a limitation associated with the field of scanning probe lithography in general (see, for example, Gates et al. Chem. Rev. 105, 1171-1196 (2005); Tseng et al., J. Vac. Sci. & Tech. B 23, 877-894 (2005)). In particular, the DPN method is generally used as a serial method rather than a parallel method, and the exponential complexity and cost arising from individually addressed feedback systems can constrain its accessibility and the rate of patterning. Therefore, a commercial need exists to improve throughput of the DPN method while maintaining its simplicity.
In many cases, the lithography has been to date carried out with one pen on one instrument to transfer a patterning compound or material to the surface. However, one approach has been to use multiple pen systems wherein multiple pens operate in parallel on one instrument. For example, WO 00/41213 to Mirkin et al. describes use of a plurality of tips with a single device, referring to U.S. Pat. No. 5,666,190 to Quate et al. (Stanford) for descriptions of cantilever arrays and nanolithographic application. In addition, WO 01/91855 to Mirkin et al. describes working examples with a plurality of tips, wherein a linear array of eight tips were obtained from a larger wafer block of tips and affixed to a ceramic tip carrier and mounted to an AFM tip holder with epoxy glue.
Salatia et al. Small, 2005, 1, No. 10, 940-945 describe parallel printing with 250 pen arrays, 26 pen arrays, and blocks of 26 pen arrays. U.S. Pat. No. 6,642,129 to Liu et al. describes parallel individually addressable probes for nanolithography including linear arrays and two dimensional arrays. The review by Ginger et al. Angew. Chem. Int. Ed. 43, 30-45 (2004)) describes 10,000 pen systems.
Massively parallel nanoarray platforms have been noted including a system with 1.2 million pens per four inch diameter wafer. See, for example, Demers et al., Genetic Engineering News, vol. 23, no. 15, Sep. 1, 2003, 32.
Parallel probes have also been developed by IBM. See for example, Vettiger et al., IBM J. Res. Dev. 2000, 44, 323; King et al., J. Microelectromech. Syst. 2002, 11, 765. See also U.S. Pat. No. 5,835,477 to Binnig et al.
However, a need yet exists to improve this approach in view of, for example, the difficulties associated with fabricating large numbers of pens in a confined space including in two dimensional arrays and in adapting the pens to a larger or customized instrument to control the printing process. For example, leveling and alignment of massive numbers of cantilevers and tips is an engineering challenge. The pens must be efficiently produced so that as many of the pens as possible are usable. Fabrication should be convenient, and the pens should be robust for commercial use with a variety of patterning compounds and materials. High rates of patterning structures, including nanostructures, are needed at high resolution and registration. While multiple pen systems have been used for patterning, the number of dots generated by contact has typically been the same as the number of pens. Otherwise, no registration exists between the two sets of dots. A need exists to better demonstrate the writing capabilities of large pen systems including better registration and alignment. This is particularly true for biomolecule technology such as protein and nucleic acid arrays.